Conventionally, a card reader has been widely utilized which is structured to read data recorded on a card and record data to a card. In an industry such as a financial institution where a card reader is utilized, illegal acquisition of magnetic data of a card by a criminal who attaches a magnetic head to a card insertion part of a card reader, in other words, so-called skimming, has conventionally become a large issue. In order to cope with the issue, a card reader has been proposed which includes a disturbing magnetic field generation part for preventing reading of magnetic data by a magnetic head for skimming (hereinafter, referred to as a “skimming magnetic head”) (see, for example, Patent Literature 1).
In the card reader described in Patent Literature 1, the disturbing magnetic field generation part includes, as shown in FIG. 6, two radiation sources 101 and 102 configured to radiate a disturbing magnetic field. The radiation sources 101 and 102 are disposed so as to interpose a conveying passage 104 for a card 103 therebetween in an upper and lower direction. Further, each of the radiation sources 101 and 102 is provided with a core 105 formed of magnetic material and a coil 106 wound around the core 105. The core 105 is formed in a substantially bottomed cylindrical tube shape as a whole and is provided with a winding core 105a in a columnar shape which is stood up from its bottom part toward an opening side of a cylindrical tube part. The coil 106 is wound around the winding core 105a. The radiation sources 101 and 102 are, as shown in FIG. 6, disposed so that, when viewed in a width direction of a card 103, imaginary lines “L101” and “L101” perpendicular to respective end faces of the winding cores 105a are inclined with respect to a passing direction of the card 103 and intersect each other to a front side of an insertion port 107 for the card 103. Further, the radiation sources 101 and 102 are disposed so that the imaginary lines “L101” and “L101” intersect each other in a thickness direction of the card 103 at a position where the card 103 is passed.
As shown in FIG. 7, a magnetic head commonly includes a core 111 formed of magnetic material, a coil 112 wound around the core 111, terminals 113 with which both end parts of the coil 112 are connected, and a case body 114 in which the core 111, the coil 112 and the terminals 113 are accommodated. The case body 114 is formed of magnetic material. A magnetic gap 111a is formed in the core 111 at one end (tip end) of the magnetic head and the coil 112 is wound around the core 111 on the other end side (base end side) of the magnetic head. Further, an opening part 114a for exposing the magnetic gap 111a is formed in the case body 114 on the tip end side of the magnetic head. On the other hand, the case body 114 is opened on the base end side of the magnetic head.
A skimming magnetic head is similarly structured to the magnetic head shown in FIG. 7 and, as shown in FIG. 6, the skimming magnetic head 110 is arranged so that its magnetic gap is capable of contacting with a magnetic stripe of a card 103. In other words, the skimming magnetic head 110 is arranged so that the tip end side of the skimming magnetic head 110 is disposed on a card 103 side. As described above, in the card reader described in Patent Literature 1, when viewed in a width direction of a card 103, the radiation sources 101 and 102 are disposed so that the imaginary lines “L101” and “L101” intersect each other on a front side with respect to the insertion port 107 for a card 103 and, in a thickness direction of the card 103, at a position where the card 103 is passed. Therefore, in the card reader, influence of a disturbing magnetic field can be effectively applied to the magnetic gap of the skimming magnetic head 110.